Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section.
In New Radio (NR), ultra-reliable and low latency communications (URLLC) is supported for emerging applications that demands high requirements on end-to-end latency and reliability. A general URLLC reliability requirement for one transmission of a packet is 1-10−5 for 32 bytes with a user plane latency of 1 ms. For URLLC, the target for user plane latency should be 0.5 ms for uplink and 0.5 ms for downlink.
The uplink grant-free transmission or the semi-persistent scheduling (SPS) transmission can be used to reduce the latency of URLLC services. The user equipment (UE) may be configured to transmit its uplink data on the configured grant without transmitting a prior request to improve the transmission latency. The network may pre-configure specific radio resources (e.g., time and frequency resources) for the UE to perform the SPS/grant-free transmissions.
In order to increase the reliability or the robustness for the URLLC transmissions, the UE may be configured to transmit repetitions for uplink information. For example, uplink grant-free transmissions may be configured with repetitions. Since the network node may allow several UEs to share the same resources on the grant-free basis, collisions between grant-free uplink UEs may happen if the resources are not enough.
Accordingly, the uplink grant-free transmission may be combined with frequency hopping schemes in order to exploit frequency diversity and reduce the impact of collisions. Therefore, it is needed to provide proper frequency hopping design for the uplink grant-free transmission.